High tension gas filled cable



March 29, 193& I HUMPH'REY 2,112,740

HIGH TENSION GAS FILLED CABLE Filed June 9, 1937 lnvento 1*.-

Daul El'iurnphw ey,

by z/ a JMZM His Attohrwey Patented Mar. 29, 1938 UNITED. STATES HIGHTENSION GAS FILLED CABLE Paul E. Humphrey, Schenectady, N. Y., assignorto General Electric Company, a corporation of New York Application June9, 1937, Serial No. 147,292

' 6 Claims. (01. 173-265) The present invention relates to cables fortransmitting high tension electric current wherein bare or uninsulatedconductors are located within a pipe and the latter filled with highpressure insulating gas. In such a cable, it is necessary to providemechanical and insulating support for the conductors so as to hold themin proper spaced relation to each other and to the inner wall of thepipe. The dielectric strength of highly compressed gas per unit ofthickness is much greater than that of solid insulations of the samethickness now available. To keep the cost of the pipe within reasonablelimits, its diameter must necessarily be restricted. This means that ifinsulators of any ordinary or usual design are interposed directlybetween the conductors and the pipe in a plane transverse to the axis ofthe pipe. they will be ineffective to properly insulate the conductors,although as me- 20 chanical supports such insulators would be quitesatisfactory. One of the problems is to provide suitable means forproperly insulating the conductors one from the other and from the pipe,and a further problem is to provide means where- 25 by the properlyinsulated conductors can be inserted into the pipe or removed therefromwhen necessary or desirable.

The object of my invention is the provision in a high tension gas filledcable of improved means 30 for supporting bare or uninsulated conductorswithin a pipe containing insulating fluid, such as gas, under adetermined pressure whereby such conductors may be readily inserted orwithdrawn from the pipe.

35 For a consideration of what I believe to be novel and my invention,attention is directed to the accompanying description and the claimsappended thereto;

In the drawing, which is illustrative of my in- 40 vention, Fig. 1 is .aview partly in section 01 a length of high tension gas filled cable;Fig.2 is a cross-sectional view of said cable; Fig. 3 is a diagrammaticview showing the relation of the conductors and their-insulatingsupports; Fig. 4

45 is a perspective view oi! the parts associated with one of theconductors; and Fig. 5 is a sectional view of a modification.

Referring especially to Figs. 1 and 2, 5 indicates a pipe which may bemade of any suitable 50 material either insulating or non-insulating.Desirably, it is made of steel. Inside of the pipe are three conductors6, I and 8 spaced 120 apart 101" carrying current under high potentialwhich are bare or have such a thin covering of insu- 56 lation as not toeffectively insulate them. The

conductors are supported on relatively long solid rods 9 of insulationwhich form chords that are inclined to the axis of the pipe. Instead ofdividing the rod into relatively short lengths, it may be made in asingle piece and bent to conform to the desired shape. The rods may bemade of any suitable material which has a relatively high dielectricstrength and is capable of supporting the weight of the conductorswithout undue bending. The rods are arranged in end to end rela- 16 tionand held in place by means to be described later. The conductors arefastened to the rods by suitable means such as clamps i0. Inclining therods in the manner shown permits of relatively wide spacing between theclamps and the ends of the rods, and in this manner an amount of solidinsulation is interposed between conducting parts which is comparable inits insulating effect to that of the high pressure insulating gas whichfills the pipe. 20

As will be seen from the drawing and particularly from Fig. 4, eachconductor has its own insulating support. In order to facilitate theintroduction of the conductors and their supports into the pipe 5,special means are provided in the form of segmental members which whenassembled define a cylinder. These members extend longitudinally of thepipe and desirably are made of preformed thin metal but which may be ofinsulation if desired. When assembled, they make a reasonably good fitwith the inner wall 0 of the pipe but should not fit too tightly becauseof the fact that they have to be moved endwise into the pipe and someallowance has to be made for irregularities in the inner surface of thepipe. Each member covers an arc of 120 degrees and has curved orinturned longitudinally extending edges I2, and also inturnedprojections l3 to form clamps. The rods 9 extend diagonally between thesaid curved edges and are anchored at their ends thereby, eachprojection l3 serving to hold the adjacent ends of two rods. The membersmay extend the full length of each pipe length or section or a number ofsuch members may be provided and arranged end to end. The members may;if desired, be lightened by removing material as indicated at it. FromFig. 4, it will clearly be seen that eachconductor with its insulatingsupports and member H form an element which is mechanically independentof the others By reference to Fig. 2, it will be seen that when thethree elements are assembled to form a cylinder with the curved edges I2of the members in en'- ga'gement, they may be slipped endwise into thepipe, either by pushing or pulling, after which the ends of theconductors of one pipe length may be united with those of the adjacentlength or lengths.

As shown in Fig. 5 each of the rods may under certain conditions supportmore than a single conductor, provided adequate spacing is providedbetween the conductors I5 and between said conductors and its supportingmember Ii.

vAfter the conductors and their supports are assembled within the pipeand the lengths of the pipe and conductors properly united, the pipe isfilled with dry insulating gas under high pressure by any suitable meansand maintained in such condition. Prior to filling the pipe with suchgas, it is desirable to remove air and any moisture contained therein,as for example by blowing a heated neutral gas, such as CO2,

clined to the axis of the pipe, a means which supports the rods atpoints remote from the conductors and itself is supported by the innerwall of the pipe, and a filling of insulating fluid under positivepressure for the pipe.

2. A cable comprising uninsulated conductors, an enclosing pipetherefor, diagonally extending rods of solid insulation for supportingthe conclusters at points midway of their length, members forindependently supporting the rods of said conductors located betweensaid rods and the pipe and forming a cylinder, and a filling ofinsulating fluid under positive pressure for the 3. A cable comprising aplurality of uninsulated conductors, an enclosing pipe therefor,insulating rods of solid insulation for supporting the conductors, asupporting means for the rods comprising segmental members correspondingin niunber to those of the conductors, said memtears when assembled withabutting edges formr ing a cylinder located within and supported by eachconductor which is supported at points remote from the conductor by theinturned edges of a member, and a filling of insulating fluid for thepipe under superatmospheric pressure.

5. A pipe cable having a support for a high tension electric conductorlocated inside of the pipe comprising a segmental member having inturnedlongitudinal edges and rod means 01' insulation extending diagonally oithe member to form chords which are supported by the said inturnededges.

6. A pipe cable having a support for a high tension electric conductorlocated within a pipe, comprising a relatively long segmental memberhaving inturned longitudinal edges, clamping means located at saidedges, and straight rods of insulation defining chords arranged in endto end relation and secured in place by the clamping means.

' Q PAUL E. HUMPHREY.

